A number of different designs of optical fiber switches are known. A typical form of such a switch is a single pole-double throw in which one fiber is physically moved into optical connection with one of two other fibers in response to some form of stimulus. Other forms, such as single pole-single throw or double pole-double throw, are also common. One problem in the design of optical fiber switches is optical alignment of the individual fibers that are optically connected. And because the fibers are fragile, a second problem concerns maintaining structural integrity of the fibers despite the fact that the switch operates by physical movement of the fibers.
Some designs use elaborate structures to solve the alignment problem. In U.S. Pat. No. 4,189,206, for example, an optical fiber is guided into a slit formed between two contact poles and through a guide hole formed by two bars traversely attached to one end of the contact poles.
The alignment problem has been partially solved by the use of grooves in which the fibers reside in the switch housing. The use of grooves of different shapes is illustrated in U.S. Pat. No. 4,152,043 to A. Albanese entitled "Electrostatic Optical Switch With Electrical Connection to Coated Optical Fiber". The use of vee-shaped grooves, such as shown in FIG. 5 of the patent, is particularly helpful for alignment purposes. The use of vee grooves is also shown in IBM Technical Disclosure Bulletin, Vol. 21, No. 11, April, 1979 in an article by J. D. Crow. The devices described by Albanese and Crow are electrostatically operated and thus require large voltages to achieve physical movement of the fiber. In addition, these and other embodiments appear to completely expose the glass fiber inside the switch housing. Because of movement of the fibers and problems of strain relief of the fibers, such embodiments appear to be structurally weak.